U.S. patent application number 12/235620 was filed with the patent office on 2009-10-15 for multi-step charge pump and method for producing multi-step charge pumping.
This patent application is currently assigned to NOVATEK MICROELECTRONICS CORP.. Invention is credited to Lan-Shan Cheng, Chih-Yuan Hsieh.
Application Number | 20090256626 12/235620 |
Document ID | / |
Family ID | 41163482 |
Filed Date | 2009-10-15 |
United States Patent
Application |
20090256626 |
Kind Code |
A1 |
Hsieh; Chih-Yuan ; et
al. |
October 15, 2009 |
MULTI-STEP CHARGE PUMP AND METHOD FOR PRODUCING MULTI-STEP CHARGE
PUMPING
Abstract
A multi-step charge pump having a power input terminal and a
power output terminal is provided. The multi-step charge pump
includes a plurality of capacitors, wherein each of the capacitors
has a capacitance. A plurality of switching devices is connected
among the capacitors, the power input terminal and the power output
terminal. A switch-controlling unit controls the on/off states of
the switches, wherein a charging-phase circuit corresponding to a
pumping level is formed to charge the capacitors and an
output-phase circuit is formed to output a voltage from the power
output terminal. At least one of the capacitors herein is
changeably selected as a voltage-regulating capacitor.
Inventors: |
Hsieh; Chih-Yuan; (Hsinchu
City, TW) ; Cheng; Lan-Shan; (Hsinchu City,
TW) |
Correspondence
Address: |
JIANQ CHYUN INTELLECTUAL PROPERTY OFFICE
7 FLOOR-1, NO. 100, ROOSEVELT ROAD, SECTION 2
TAIPEI
100
TW
|
Assignee: |
NOVATEK MICROELECTRONICS
CORP.
Hsinchu
TW
|
Family ID: |
41163482 |
Appl. No.: |
12/235620 |
Filed: |
September 23, 2008 |
Current U.S.
Class: |
327/536 |
Current CPC
Class: |
H02M 3/07 20130101; H02M
3/073 20130101 |
Class at
Publication: |
327/536 |
International
Class: |
G05F 1/10 20060101
G05F001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 14, 2008 |
TW |
97113493 |
Claims
1. A multi-step charge pump, having a power input terminal and a
power output terminal, the charge pump comprising: a plurality of
capacitors, wherein each of the capacitors respectively has a
capacitance; a plurality of switching devices, connected among the
capacitors, the power input terminal and the power output terminal;
and a switch-controlling unit for controlling on/off states of the
switching devices, wherein a charging-phase circuit corresponding
to a desired pumping level is formed for charging the capacitors
and an output-phase circuit is formed to output a voltage from the
power output terminal, wherein at least one of the capacitors is
changeably selected as a voltage-regulating capacitor.
2. The multi-step charge pump according to claim 1, wherein the
capacitances of all the capacitors are the same.
3. The multi-step charge pump according to claim 1, wherein the
capacitances of the capacitors are not all the same.
4. The multi-step charge pump according to claim 1, wherein the
number of the capacitors is at least three.
5. The multi-step charge pump according to claim 1, wherein the
output-phase circuit comprises: a first circuit, formed by at least
a part of the capacitors other than the voltage-regulating
capacitor, wherein the capacitors to form the first circuit are
connected by the switching devices and the first circuit is between
the power input terminal and a grounded terminal; and a second
circuit, comprising the voltage-regulating capacitor and connected
between the power input terminal and a grounded terminal.
6. The multi-step charge pump according to claim 1, wherein the
charging-phase circuit comprises: a first circuit, formed by at
least a part of the capacitors other than the voltage-regulating
capacitor, wherein the capacitors to form the first circuit are
connected by the switching devices and the first circuit has a
first connection terminal connected to the power input terminal and
a second connection terminal; and a second circuit, comprising the
voltage-regulating capacitor and connected between the power input
terminal and a grounded terminal, wherein the power output terminal
is connected to the second connection terminal of the first
circuit.
7. The multi-step charge pump according to claim 1, wherein the
power output terminal is connected to the voltage-regulating
capacitor through the switching devices.
8. A method for producing a multi-step charge pumping, used to
change a first voltage into a second voltage, the method
comprising: providing a plurality of capacitors, wherein each of
the capacitors has a capacitance; providing a plurality of
switching devices; connecting the switching devices among the
capacitors, the power input terminal and the power output terminal;
changeably selecting at least one among the capacitors as a
voltage-regulating capacitor; during a first phase, controlling the
switching devices to obtain a charging-phase circuit corresponding
to a desired pumping level so as to allow the capacitors charged by
the first voltage; and during a second phase, controlling the
switching devices to obtain an output-phase circuit corresponding
to the desired pumping level so as to output the second voltage,
wherein the voltage-regulating capacitor is between the second
voltage and a grounded voltage.
9. The method for producing a multi-step charge pumping according
to claim 8, wherein in the step of providing the capacitors, the
capacitances of all the capacitors are the same.
10. The method for producing a multi-step charge pumping according
to claim 8, wherein in the step of providing the capacitors, the
capacitances of the capacitors are not all the same.
11. The method for producing a multi-step charge pumping according
to claim 8, wherein in the step of providing the capacitors, the
number of the capacitors is at least three.
12. The method for producing a multi-step charge pumping according
to claim 8, wherein the method to obtain the output-phase circuit
comprises: wiring at least a part of the capacitors other than the
voltage-regulating capacitor by the switch devices to form a first
circuit connected between the power input terminal and a grounded
terminal; and connecting the voltage-regulating capacitor between
the power output terminal and the grounded terminal to form a
second circuit.
13. The method for producing a multi-step charge pumping according
to claim 8, wherein the method to obtain the charging-phase circuit
comprises: wiring at least a part of the capacitors other than the
voltage-regulating capacitor by the switching devices to form a
first circuit having a first connection terminal connected to the
power input terminal and a second connection terminal; and
connecting the voltage-regulating capacitor between the power
output terminal and the grounded terminal to form a second
circuit.
14. The method for producing a multi-step charge pumping according
to claim 8, further comprising connecting the power output terminal
to the voltage-regulating capacitor through the switching devices
and connecting the power output terminal to an external load
circuit.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 97113493, filed on Apr. 14, 2008. The
entirety of the above-mentioned patent application is hereby
incorporated by reference herein and made a part of
specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to the technique of multi-step
charge pump.
[0004] 2. Description of Related Art
[0005] A multi-step charge pump is used to, for example, change an
input voltage into another input voltage, wherein the multi-step
charge pump has multiple pumping levels, which can be pulled-up
voltage levels or pulled-down voltage levels. In general, a
multi-step charge pump is composed of a plurality of capacitors. In
terms of a conventional multi-step charge pump, the output terminal
thereof is electrically connected to a load to be driven; but for
achieving a stable operation voltage, the load would be connected
in parallel to an unchangeable capacitor and the unchangeable
capacitor is termed as voltage-regulating capacitor.
[0006] FIG. 1 is a circuit diagram of a conventional charge pump.
Referring to FIG. 1, a charge pump 100 is formed by two capacitors
102 and 104 and a voltage-regulating capacitor 106, wherein the
voltage-regulating capacitor 106 is unchangeably in parallel
connection with a load unit 120, and the voltage-regulating
capacitor 106 together with the load unit 120 is connected between
an output voltage Vo and a ground voltage. The capacitances of the
capacitors 102 and 104 and the voltage-regulating capacitor 106 are
respectively represented by C1, C2 and C3.
[0007] In the above-mentioned conventional charge pump composed of
three capacitors, the capacitances thereof are, for example, the
same, i.e., C1=C2=C3. The voltage-regulating capacitor 106 is
connected to a grounded terminal all the time, and the terminals of
other five capacitors are connected to an integrated circuit (IC).
The pump is able to produce multiple voltages with different
factors. FIG. 2 is a diagram showing various wiring circuits of the
capacitors in the conventional charge pump of FIG. 1, wherein the
wiring circuits produce a plurality of factors of voltage and the
capacitors C1, C2 and C3 are subject to C1=C2=C3. Referring to FIG.
2, the charge pump herein is operated in two phases. The left
circuits of the dotted lines are operated in charging-phase, and
the right circuits of the dotted lines are operated in
output-phase, wherein there are four factors of voltage: triple
(3.times.), double (2.times.), one and a half times (1.5.times.),
and half (0.5.times.) which are produced respectively by the
circuits of FIGS. 2(a), 2(b), 2(c) and 2(d).
[0008] In FIG. 2(a), the conventional charge pump requires a
capacitor unchangeably as the voltage-regulating capacitor and the
capacitor 106 unchangeably serves as the voltage-regulating
capacitor of an output voltage Vo. During the charging-phase, the
capacitors 102 (C1) and 104 (C2) are charged by an input voltage
Vin so as to make 102 and 104 store Vin. During the output-phase,
the connection between the capacitors 102 and 104 is switched to
serial connection, and the input voltage Vin is connected in series
to a negative voltage terminal and another terminal thereof is
connected to a voltage output terminal, so that Vo is boosted to a
voltage three times greater than the voltage Vin. In FIG. 2(b), the
capacitor 106 still serves as the voltage-regulating capacitor of
Vo. During the charging-phase, the capacitor 102 (C1) is charged by
Vin to store the voltage Vin; meanwhile, Vin is connected to the
negative voltage terminal of the capacitor 104 (C2). Another
terminal of the capacitor 104 (C2) is connected to the output
terminal so as to boost Vo to a voltage double of the voltage Vin.
During the output-phase, the capacitor 104 (C2) is charged by the
input voltage Vin so as to make the capacitor 104 (C2) store Vin;
meanwhile, Vin is connected to the negative voltage terminal of the
capacitor 102 (C1). Another terminal of the capacitor 102 (C1) is
connected to the output terminal so as to boost Vo to a voltage
double of the voltage Vin. In FIG. 2(c), the capacitor 106 (C3)
unchangeably serves as the voltage-regulating capacitor of Vo.
During the charging-phase, the capacitors 102 and 104 in series
connection are charged by Vin so as to make both capacitors store
voltage of 0.5 Vin. During the output-phase, Vin is connected to
the negative voltage terminal of the circuit formed by the
capacitors 102 and 104 in parallel connection. Another terminal of
the parallel circuit is connected to the output terminal to boost
Vo to a voltage of 1.5 Vin. In FIG. 2(d), the capacitor 106 (C3)
still unchangeably serves as the voltage-regulating capacitor of
Vo. During the charging-phase, the capacitors 102 and 104 in series
connection are charged by Vin to store the voltage of 0.5 Vin.
During the output-phase, Vin is connected to the positive voltage
terminal of the circuit formed by the capacitors 102 and 104 in
parallel connection. Another terminal of the parallel circuit is
connected to the output terminal to down push Vo to the voltage of
0.5 Vin. The factors of voltage produced by the pump are fixed and
thus unchangeable to meet the user demand.
[0009] FIG. 3 is a diagram of showing various wiring circuits of
the capacitors in another conventional charge pump. Differently
from FIG. 2, the capacitances C1, C2 and C3 of three capacitors 102
that 104 and 106 in FIG. 3 are subject to C1:C2:C3=a:b:c, and
a.noteq.b.noteq.c; thus, the charge pump in FIG. 3 can produce
multiple voltages in different factors. Similarly to the circuits
of FIGS. 2(a) and 2(b), the circuits of FIGS. 3(a) and 3(b) can
respectively produce a triple voltage and a double voltage. In FIG.
3(c), the capacitor 106 (C3) unchangeably serves as the
voltage-regulating capacitor of Vo. During the charging-phase, the
capacitors 102 (C1) and 104 (C2) in series connection are charged
by Vin so as to make the capacitor 102 store voltage of
[b/(a+b)].times.Vin and the capacitor 104 store voltage of
[a/(a+b)].times.Vin. During the output-phase,
Vo=Vin-[b/(a+b)].times.Vin+[a/(a+b)].times.Vin=[2a/(a+b)].times.Vin.
In FIG. 3(d), the capacitor 106 still unchangeably serves as the
voltage-regulating capacitor of Vo. During the charging-phase, the
capacitors 102 (C1) and 104 (C2) in series connection are charged
by Vin so as to make 102 (C1) store the voltage of
[b/(a+b)].times.Vin and the capacitor 104 (C2) store the voltage of
[a/(a+b)].times.Vin. During the output-phase,
Vo=Vin+[b/(a+b)].times.Vin-[a/(a+b)].times.Vin=[2b/(a+b)].times.Vin.
The charge pump of FIG. 3 is able to adjust the capacitance ratio
between the employed capacitors according to the desired factor of
voltage.
[0010] FIG. 4 is a circuit diagram of yet another conventional
charge pump. Referring to FIG. 4, the charge pump 100 is an
enhanced one of FIG. 1, where a capacitor 108 is additionally
employed for producing more pumping levels. The employed four
capacitors 102, 104, 106 and 108 have the same capacitances, i.e.,
C1=C2=C3=C4, wherein the voltage-regulating capacitor 106 (C4)
serves as the voltage-regulating capacitor and a terminal thereof
is connected to a grounded terminal all the time, and the rest
seven terminals of the capacitors 102, 104, 106 and 108 are
connected to an IC. The charge pump herein is able to produce
multiple voltages with different times, such as quadruple
(4.times.), triple (3.times.), two and a half times (2.5.times.),
double (2X), one and a half times (1.5.times.), 1.66 times
(1.66.times.), 1.33 times (1.33.times.), 0.66 times (0.66.times.),
a half (0.5.times.) and 0.33 times (0.33.times.).
[0011] FIGS. 5A-5B are diagrams showing various switching circuits
respectively for a factor in the conventional charge pump 100 of
FIG. 4. In FIG. 5A(a), the capacitor 106 (C4) unchangeably serves
as the voltage-regulating capacitor of an output voltage Vo. During
the charging-phase, the capacitors 102 (C1), 104 (C2) and 108 (C3)
in parallel connection are charged by an input voltage Vin so as to
make them store Vin. During the output-phase, Vin is connected to
the negative voltage terminal where the capacitors 102 (C1), 104
(C2) and 108 (C3) are connected in series to and another terminal
thereof is connected to a voltage output terminal, so that Vo is
boosted to a voltage of 4 Vin. In FIG. 5A(b), the capacitor 106
(C4) still serves as the voltage-regulating capacitor of Vo. During
the charging-phase, the capacitors 102 (C1), 104 (C2) and 108 (C3)
are charged by Vin to store the voltage Vin. During the
output-phase, the capacitors 102 (C1) and 104 (C2) are connected in
parallel to each other, followed by connecting in series them to
the capacitor 108 (C3). Vin is connected to the negative voltage
terminal of the capacitors 102 (C1) and capacitor 104 (C2) in
parallel connection, and another terminal thereof is connected to
the output terminal so as to boost Vo to a voltage of 3 Vin. In
FIG. 5A(c), within the charging-phase, the capacitors 102 (C1), 104
(C2) and 108 (C3) are charged by Vin so as to make the capacitor
108 (C3) store a voltage of Vin, and the 102 (C1) and 104 (C2)
store a voltage of 0.5 Vin. During the output-phase, the capacitors
102 (C1) and 104 (C2) are connected in parallel to each other,
followed by connecting in series them to the capacitor 108 (C3).
Then, Vin is connected to the negative voltage terminal of the
capacitors 102 (C1) and capacitor 104 (C2) in parallel connection,
and another terminal thereof is connected to the output terminal so
as to boost Vo to a voltage of 2.5 Vin. In FIG. 5A(d), within the
charging-phase, the capacitors 102 (C1), 104 (C2) and 108 (C3) are
charged by Vin to store a voltage of Vin. During the output-phase,
Vin is connected to the negative voltage terminal of the capacitors
102 (C1), capacitor 104 (C2) and capacitor 108 (C3) in parallel
connection, and another terminal thereof is connected to the output
terminal so as to boost Vo to a voltage of 2Vin. In FIG. 5A(e),
within the charging-phase, the capacitors 102 (C1), 104 (C2) and
108 (C3) are charged by Vin to make the capacitor 108 (C3) store a
voltage of Vin and the capacitors 102 (C1) and 104 (C2) store a
voltage of 0.5 Vin. During the output-phase, Vin is connected to
the positive voltage terminal of the capacitors 102 (C1) and
capacitor 104 (C2) in parallel connection, followed by connecting
in series them to the negative terminal of the capacitor 108 (C3);
another terminal thereof is connected to the output terminal so as
to boost Vo to a voltage of 1.5 Vin. In this way, by properly
wiring the circuit of the capacitors, other pumping levels can be
produced. The circuits of FIGS. 5A(f), 5B(g), 5B(h), 5B(i) and
5B(j) respectively produce 1.66 Vin, 1.33 Vin, 0.66 Vin, 0.5 Vin
and 0.33 Vin, and these are well known for anyone skilled in the
art and omitted to describe.
[0012] A conventional charge pump requires an unchangeable
capacitor as a voltage-regulating capacitor corresponding to a
load. With the conventional charge pump, several external
capacitors with the same capacitance are used; therefore, the
produced voltage combinations are fixed and unable to be changed to
obtain an optimal factor of voltage for different applications,
which may results in a poor efficiency for some application
voltages.
SUMMARY OF THE INVENTION
[0013] Accordingly, the present invention is directed to a
multi-step charge pump and a method for producing the multi-step
charge pumping, which can produce different voltage combinations in
association with different load operation voltages so as to promote
the efficiency of the charge pump and make the charge pump more
broadly applied.
[0014] The present invention provides a multi-step charge pump
having a power input terminal and a power output terminal. The
multi-step charge pump includes a plurality of capacitors and each
of the capacitors respectively has a capacitance. A plurality of
switching devices is connected among the capacitors, the power
input terminal and the power output terminal. A switch-controlling
unit controls the on/off states of the switching devices to form a
charging-phase circuit corresponding to a desired pumping level for
charging the capacitors and to form an output-phase circuit to
output a voltage from the power output terminal. At least one of
the capacitors herein is changeably selected as a
voltage-regulating capacitor.
[0015] According to an embodiment of the present invention, in the
above-mentioned multi-step charge pump, the capacitances of the
capacitors are, for example, the same or not all the same.
[0016] According to an embodiment of the present invention, in the
above-mentioned multi-step charge pump, the output-phase circuit
thereof includes, for example, a first circuit and a second
circuit. The first circuit is formed by at least a part of the
capacitors other than the voltage-regulating capacitor, wherein the
capacitors to form the first circuit are connected by the switching
devices. The first circuit is between the power input terminal and
a grounded terminal. The second circuit includes the
voltage-regulating capacitor and is connected between the power
input terminal and a grounded terminal.
[0017] According to an embodiment of the present invention, in the
above-mentioned multi-step charge pump, the charging-phase circuit,
for example, includes a first circuit and a second circuit. The
first circuit is formed by at least a part of the capacitors other
than the voltage-regulating capacitor, wherein the capacitors to
form the first circuit are connected by the switching devices. The
first circuit has a first connection terminal connected to the
power input terminal and a second connection terminal. The second
circuit includes the voltage-regulating capacitor connected between
the power input terminal and a grounded terminal, wherein the power
output terminal is connected to the second connection terminal of
the first circuit.
[0018] The present invention provides a method for producing a
multi-step charge pumping to change a first voltage into a second
voltage. The method includes: providing a plurality of capacitors,
wherein each of the capacitors has a capacitance; providing a
plurality of switching devices; connecting the switching devices
among the capacitors, the power input terminal and the power output
terminal; changeably selecting at least one among the capacitors as
a voltage-regulating capacitor; within a first phase, controlling
the switching devices to obtain a charging-phase circuit
corresponding to a desired pumping level so as to allow the
capacitors charged by the first voltage; within a second phase,
controlling the switching devices to obtain an output-phase circuit
corresponding to the desired pumping level so as to output the
second voltage, wherein the voltage-regulating capacitor is between
the second voltage and a grounded voltage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Other objectives, features and advantages of the present
invention will be further understood from the further technological
features disclosed by the embodiments of the present invention
wherein there are shown and described preferred embodiments of this
invention, simply by way of illustration of modes best suited to
carry out the invention.
[0020] FIG. 1 is a circuit diagram of a conventional charge
pump.
[0021] FIG. 2 is a diagram showing various wiring circuits of the
capacitors in the conventional charge pump of FIG. 1, wherein the
wiring circuits produce a plurality of factors of voltage and the
capacitors C1, C2 and C3 are subject to C1=C2=C3.
[0022] FIG. 3 is a diagram of showing various wiring circuits of
the capacitors in another conventional charge pump.
[0023] FIG. 4 is a circuit diagram of yet another conventional
charge pump.
[0024] FIGS. 5A-5B are diagrams showing various switching circuits
respectively for a factor in the conventional charge pump 100 of
FIG. 4.
[0025] FIG. 6 is a circuit diagram of a multi-step charge pump
according to an embodiment of the present invention.
[0026] FIGS. 7A-7B are diagrams showing various combinations of the
multi-step charge pumps of FIG. 6 according to an embodiment of the
present invention.
[0027] FIG. 8 is a circuit diagram of a multi-step charge pump
according to another embodiment of the present invention.
[0028] FIG. 9 is a diagram showing various combinations of the
multi-step charge pumps of FIG. 8 according to the embodiment of
the present invention.
[0029] FIG. 10 is a circuit diagram of a multi-step charge pump
according to another embodiment of the present invention.
[0030] FIG. 11 is an application circuit diagram of the multi-step
charge pump of FIG. 10 according to an embodiment of the present
invention.
DESCRIPTION OF THE EMBODIMENTS
[0031] Reference will now be made in detail to the present
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers are used in the drawings and the description
to refer to the same or like parts.
[0032] The multi-step charge pump of the present invention features
that one of the capacitors thereof serving as the
voltage-regulating capacitor implemented through controlling of the
switch-controlling unit in the multi-step charge pump is not
unchangeable one as the prior art. With the above-mentioned scheme,
the multi-step charge pump of the present invention not only
produces more factors of voltage, but also has an adjustable factor
of voltage at any time so as to operate the multi-step charge pump
without limitation to a fixed factor. In other words, a plurality
of circuits is timely formed by switching the connections so as to
produce different pumping levels and increase more different
voltage combinations. Since there is no unchangeable
voltage-regulating capacitor in the multi-step charge pump of the
present invention, thus, the capacitors thereof can be more
effectively used and the different factors of voltage can be
selected to meet the requirement of different output voltages.
[0033] Several employments are depicted as follows, but the present
invention does not limit the following embodiments.
[0034] FIG. 6 is a circuit diagram of a multi-step charge pump
according to an embodiment of the present invention. Referring to
FIG. 6, where three capacitors are exemplarily used. A multi-step
charge pump 200 includes three capacitors 202, 204 and 206
respectively having capacitances of C1, C2 and C3. The application
circuit of the multi-step charge pump is illustrated in FIG. 11 in
more detail. None of the capacitors in the multi-step charge pump
200 is unchangeably specified as a voltage-regulating capacitor;
that is, any one of the capacitors 202, 204 and 206 can be wired to
form a circuit combination for required output voltage and at least
one capacitor among them is selected as the voltage-regulating
capacitor to meet the need.
[0035] FIGS. 7A-7B are diagrams showing various combinations of the
multi-step charge pumps of FIG. 6 according to an embodiment of the
present invention. Referring to FIGS. 7A and 7B, since none of the
three capacitors is unchangeably used as a voltage-regulating
capacitor, there are more circuit combinations. The capacitors 202,
204 and 206 capacitors 202, 204 and 206 have capacitances of C1, C2
and C3, and C1:C2:C3=a:b:c, wherein a, b and c can be equal to each
other or partially equal, for example, a.noteq.b.noteq.c. There are
eight factors of voltage in total in FIGS. 7A and 7B corresponding
to circuits of (a)-(h), which are respectively triple, double,
[2a/(a+b)] times, [2b/(a+b)] times, [2c/(b+c)] times, [2b/(b+c)]
times, [2a/(c+a)] times and [2c/(c+a)] times.
[0036] In FIG. 7A(a), for example, the capacitor 206 (C3) serves as
the voltage-regulating capacitor of an output voltage Vo. During
the charging-phase, the capacitors 202 (C1) and 204 (C2) are
charged by an input voltage Vin so as to make them store Vin.
During the output-phase, Vin is connected to the negative voltage
terminal of a circuit with the capacitors 202 (C1) and 204 (C2)
connected in series, and another terminal of the circuit is
connected to a voltage output terminal, so that Vo is boosted to a
voltage of 3Vin. In FIG. 7A(b), for example, the capacitor 206 (C3)
serves as the voltage-regulating capacitor of Vo. During the
charging-phase, the capacitors 202 (C1) is charged by Vin to store
the voltage Vin, and meanwhile, Vin is connected to the negative
voltage terminal of the capacitor 204 (C2) and another terminal
thereof is connected to the output terminal so as to boost Vo to 2
Vin. During the output-phase, the capacitor 204 (C2) is charged to
store the voltage Vin, meanwhile, Vin is connected to the negative
voltage terminal of the capacitor 202 (C1) and another terminal of
the capacitor 202 (C1) is connected to the output terminal to boost
Vo to a voltage of 2 Vin. In FIG. 7A(c), for example, the capacitor
206 (C3) still serves as the voltage-regulating capacitor of Vo.
During the charging-phase, the capacitors 202 (C1) and 204 (C2) in
series connection are charged by Vin so as to make the capacitor
202 (C1) store a voltage of [b/(a+b)].times.Vin, and the capacitor
204 (C2) store a voltage of [a/(a+b)].times.Vin. During the
output-phase, Vo is equal to [2a/(a+b)].times.Vin. In FIG. 7A(d),
the output terminal can obtain the voltage of [2a/(a+b)].times.Vin
as well. Similarly to the described above, by selecting different
capacitor as the voltage-regulating capacitor, a plurality of
factors of voltage, such as [2c/(b+c)] times, [2b/(b+c)] times,
[2a/(c+a)] times and [2c/(c+a)] times can be obtained as shown by
FIGS. 7B(e)-7B(h). Since the voltage-regulating capacitor is not
unchangeably assigned to the capacitor 206, thus, more factors of
voltage can be produced. In addition, if the capacitances of the
three capacitors are unequal to each other, far more factors of
voltage than the described above can be produced.
[0037] FIG. 8 is a circuit diagram of a multi-step charge pump
according to another embodiment of the present invention. Referring
to FIG. 8, the embodiment, for example, takes four capacitors to
form a multi-step charge pump. The four capacitors 202 (C1), 204
(C2), 206 (C3) and 208 (C4) in series connection herein have
capacitances of C1, C2, C3 and C4, and C1:C2:C3:C4=a:b:c:d, wherein
a, b, c and d can be equal to each other or partially equal, for
example, a.noteq.b.noteq.c.noteq.d. The multi-step charge pump of
the embodiment produces a plurality of factors of voltage, for
example, quadruple, triple, double, [2+2a/(a+b)] times,
[2ab/(ac+bc+ab)] times, [(2ab+2ac)/(ac+bc+ab)] times . . . and so
on.
[0038] FIG. 9 is a diagram showing various combinations of the
multi-step charge pumps of FIG. 8 according to the embodiment of
the present invention. Note that if at least one capacitor in
series connection, for example two capacitors in series connection
in FIG. 9, is selected as a voltage-regulating capacitor; then, the
embodiment of FIG. 9 has the similar mechanism as that of FIG. 6
where three capacitors are used. In the following embodiment
however, for example, one of the capacitors is changeably selected
as the voltage-regulating capacitor. Referring to FIGS. 9(a), 9(b)
and 9(c), the corresponding circuits respectively produce factors
of voltage of four times, three times and two times. In addition,
the multi-step charge pump herein has more circuit combinations, so
that the circuits of FIGS. 9(d), 9(e) and 9(f) can respectively
produce factors of voltage, for example, [2+2a/(a+b)] times,
[2ab/(ac+bc+ab)] times and [(2ab+2ac)/(ac+bc+ab)] times . . . and
so on.
[0039] For example in FIG. 9(d), the capacitor 208 (C4) is selected
as the voltage-regulating capacitor. Continuing to FIG. 9(d),
within the charging-phase, the capacitors 202 (C1) and capacitor
206 (C3) are charged by an input voltage Vin so as to make the
capacitor 202 (C1) store a voltage of [b/(a+b)].times.Vin, the
capacitor 204 (C2) store a voltage of [a/(a+b)].times.Vin and the
capacitor 206 (C3) store a voltage of Vin. During the output-phase,
Vin is connected to the negative voltage terminal of a
series-connection circuit with the capacitors 204 (C2) and 206 (C3)
connected in series and further connecting to the positive terminal
of the capacitor 202 (C1) in series. Another terminal of the
series-connection circuit is connected to the output terminal, so
that Vo is boosted to a voltage of [2+2a/(a+b)].times.Vin. In this
way, by selecting different capacitors as a voltage-regulating
capacitor, more factors of voltage can be produced.
[0040] In FIG. 9(e), Vo is boosted to a voltage of
[2ab/(ac+bc+ab)].times.Vin according to the configuration of the
circuit. In FIG. 9(f), Vo is boosted to a voltage of
[(2ab+2ac)/(ac+bc+ab)].times.Vin according to another configuration
of the circuit. It can be seen that more produced factors of
voltage can be obtained by changing the sequence of the employed
capacitors.
[0041] FIG. 10 is a circuit diagram of a multi-step charge pump
according to another embodiment of the present invention. Referring
to FIG. 10, a multi-step charge pump 300 includes a plurality of
capacitors 302, 304, . . . , 306 respectively having capacitances
of C1, C2, . . . , Cn. By changeably selecting at least one of the
capacitors 302, 304, . . . , 306 as a voltage-regulating capacitor,
the desired factors of voltage of the pump can be produced.
[0042] FIG. 11 is an application circuit diagram of the multi-step
charge pump of FIG. 10 according to an embodiment of the present
invention. Referring to FIG. 11, a multi-step charge pump 300
includes a plurality of capacitors 302, 304, . . . , 306
respectively having capacitances of C1, C2, . . . , Cn. The power
input terminal and the power output terminal are selected according
to the configurations of the circuit, wherein the power output
terminal has a voltage, such as Vout, and is connected to a load
400. The power input terminal can be, for example, a terminal of
the selected capacitor and connected to an input voltage Vin. A
plurality of switching devices 308 is electrically connected the
capacitors between the power input terminal and the power output
terminal. A switch-controlling unit 310 controls the on/off states
of the switching devices 308. A charging-phase circuit is formed
according to a desired pumping level to charge the capacitors and
an output-phase circuit is also formed to output a voltage with an
altered factor from the power output terminal Vout. At least one of
the capacitors 302, 304, . . . , 306 is changeably selected as a
voltage-regulating capacitor.
[0043] By using the switch-controlling unit 310 to control the
switching devices 308 to select at least one capacitor as a
voltage-regulating capacitor of the multi-step charge pump, the
present invention is able to form a charging-phase circuit and an
output-phase circuit corresponding to a desired factor of voltage.
As a result, the multi-step charge pump of the present invention
has more factors of voltage to provide a desired voltage to drive a
load 400.
[0044] According to the present invention, the method for producing
a multi-step charge pumping is used to change a first voltage into
a second voltage. The method includes: providing a plurality of
capacitors, wherein each of the capacitors has a capacitance;
providing a plurality of switching devices; connecting the
switching devices to the capacitors between the power input
terminal and the power output terminal; changeably selecting at
least one among the capacitors as a voltage-regulating capacitor;
during a first phase, controlling the switching devices to obtain a
charging-phase circuit corresponding to a desired pumping level so
as to allow the capacitors charged by the first voltage; during a
second phase, controlling the switching devices to obtain an
output-phase circuit corresponding to the desired pumping level so
as to output the second voltage, wherein the voltage-regulating
capacitor is between the second voltage and a grounded voltage.
[0045] The foregoing description of the preferred embodiment of the
invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form or to exemplary embodiments
disclosed. Accordingly, the foregoing description should be
regarded as illustrative rather than restrictive. Obviously, many
modifications and variations will be apparent to practitioners
skilled in this art. The embodiments are chosen and described in
order to best explain the principles of the invention and its best
mode practical application, thereby to enable persons skilled in
the art to understand the invention for various embodiments and
with various modifications as are suited to the particular use or
implementation contemplated. It is intended that the scope of the
invention be defined by the claims appended hereto and their
equivalents in which all terms are meant in their broadest
reasonable sense unless otherwise indicated. Therefore, the term
"the invention", "the present invention" or the like is not
necessary limited the claim scope to a specific embodiment, and the
reference to particularly preferred exemplary embodiments of the
invention does not imply a limitation on the invention, and no such
limitation is to be inferred. The invention is limited only by the
spirit and scope of the appended claims. The abstract of the
disclosure is provided to comply with the rules requiring an
abstract, which will allow a searcher to quickly ascertain the
subject matter of the technical disclosure of any patent issued
from this disclosure. It is submitted with the understanding that
it will not be used to interpret or limit the scope or meaning of
the claims. Any advantages and benefits described may not apply to
all embodiments of the invention. It should be appreciated that
variations may be made in the embodiments described by persons
skilled in the art without departing from the scope of the present
invention as defined by the following claims. Moreover, no element
and component in the present disclosure is intended to be dedicated
to the public regardless of whether the element or component is
explicitly recited in the following claims.
* * * * *